- Overview
- Manual Slack Adjusters (MSA)
- Automatic Slack Adjusters (ASA)
- Components of Slack Adjusters
Manual brake adjusters contain four basic components; the body, worm gear, worm shaft, and locking screw or collar.
The worm shaft of the brake adjuster incorporates an external adjusting hex. Turning the adjusting hex rotates the worm shaft which turns the worm gear and brake scam shaft, thus spreading the brake shoes and reducing drum-to-lining clearance.
Light to medium gross axle weight rating (GAWR) vehicles utilize either a spring-loaded locking sleeve or a lock ball indent adjustment lock to prevent the worm shaft from backing off.
Higher torque-rated brake adjusters use the lock ball or plunger or worm shaft indent principle adjustment lock. The lock ball or plunger must engage the worm shaft indent after the adjustment is completed. An audible metallic click will be heard when engagement is made.